A conventional revolving door system including four doors radially extending from a vertically extending center supporting shaft has a disadvantageously narrow space defined between adjacent doors. Jacob Robert Alfred Hoover et al. filed a Japanese patent application, laid open for public inspection as Japanese Unexamined Patent Publication (KOKAI) No. SHO 56-481 A on Jan. 6, 1981, claiming a priority from Dutch Patent Application No. 7902203 filed on Mar. 21, 1979. In this patent publication, they proposed a revolving door system free of the above-described disadvantage of conventional revolving doors. The doors of Japanese Unexamined Patent Publication (KOKAI) No. SHO 56-481 A do not revolve along a circular path, but they move along a racetrack-shaped path defined by two parallel straight lines and two arcs each connecting the ends of the two straight lines on the same side. Each door is supported by a frame. Although the details of the structure of the revolving door system is not clearly shown in the patent publication, it seems that each door frame of the system, as best understood, includes a vertically extending member and horizontal members extending from the top and bottom ends of the vertical member. One of the longer sides of the door is connected to the vertical member with hinges. The door is supported in such a manner that free rotation of the door about the hinges is prevented by some restraining means operating from spring force.
The door system of the Japanese patent publication has a disadvantage that it cannot withstand against a large external force exerted to the doors. When, for example, some large wind pressure is exerted to the door, it may rotate open about the hinges since the rotation restraining means acts on the side of the door where the hinges are attached. Therefore it is desirable that the doors can withstand such external force exerted to them.
In addition, it is desired that revolving door systems have many other functions, but it is important that provision of such functions should not deface the door system since it may be installed in the doorway of a building which is exposed to public.
An object of the present invention is to provide a revolving door system which can withstand wind pressure of some magnitude, and which is provided with many functions and still has an esthetically good appearance.
According the present invention, a revolving door system is provided. The revolving door system includes outer walls disposed in parallel with a doorway in a building wall and connected to the building wall. A hollow center core is disposed between the outer walls, and it includes parallel straight portions which have a length substantially equal to the length of the outer walls and are in parallel with the outer walls. The center core further includes two arcuate end portions each connecting respective two adjacent ends of the straight portions. A ceiling member is disposed to extend above the center core and the outer walls across the doorway. The ceiling member, the floor of the doorway, the center core and the outer walls defining two passageways. Parallel, spaced upper and lower rails are disposed within the center core. The rails extend horizontally in parallel with the outer surface of the center core. Plural sets of upper and lower suspension devices are disposed one for each door. The upper and lower suspension devices movably engage with the upper and lower rails, respectively, so as to move along them. A plurality of doors are supported by the respective sets of upper and lower suspension devices so as to be movable through the passageways. A plurality of pulling bars are secured to the respective upper suspension devices. A door driving chain driven by a door driving arrangement is connected to the respective pulling bars.
A door supporting structure for supporting each of the doors includes a carrier bar. The carrier bar is coupled to each of the upper suspension devices. Each carrier bar extends in parallel with the ceiling member and has a length substantially equal to the width of the door. The upper portion of each door is rotatably carried by the carrier bar at a location near the center core. The lower portion of each door is rotatably supported by the lower suspension device at a location near the center core.
The upper portion of each door is detachably held by the associated carrier bar at a location remote from the location where the door is carried by the carrier bar.
Since each door is supported at two points along its upper portion and at one point along the lower portion, it can have an improved resistance to external force, such as wind pressure.
According to a second feature of the present invention, the revolving door system includes vertical supports, one for each door. Each vertical support extends in parallel with the outer surface of the center core. The upper end of the vertical support is secured to the center-core side of the carrier bar for that door, while its lower end is connected to the lower suspension device for that door. Each door is disposed with its longer sides extending along the vertical support. The upper portion of the door is rotatably supported at a location near to the vertical support by the carrier bar, while the lower portion of the door is rotatably supported by the lower suspension device. The upper side of each door is detachably held by the carrier bar at a location remote from the location where the door is rotatably supported by the carrier bar.
According to the second feature, by virtue of the use of the vertical supports, the respective carrier bars are firmly held by the associated vertical supports and the associated upper and lower suspension devices, and, therefore, the resistance of each door against external force is further improved.
The detachable holding of the upper portion of each door by the carrier bar may be provided by means of an electromagnetic locking arrangement. When the electromagnetic locking arrangement is energized, the door is held at three points so as to exhibit an improved resistance to external force, and when the electromagnetic locking arrangement is deenergized, the door can be swung open about an axis located near the center core.
According to a third feature, each of the carrier bars is formed of a hollow member. The hollow carrier bar may house therein a bearing for rotatably supporting the associated door, an arrangement for detachably holding the door, a sensor for sensing an object immediately before the door, and other accessories. The placing of such components in the hollow carrier bars makes the revolving door system look tidy in appearance. A number of sensors required for forming a desired number or size of sensing regions may be disposed in the carrier bars. The sensors may be reflection-type optical sensors.
According to a fourth feature of the present invention, each of the carrier, bars is formed of a hollow member for housing therein a bearing for rotatably holding the upper portion of an associated door at a location near the center core. An automatic door closing arrangement is disposed for each door within and in parallel with the ceiling member. Each pulling bar has a linking member secured, together with the associated carrier bar, to the associated upper suspension device. The automatic door closing arrangement is disposed along the pulling bar, and is linked to the rotation shaft of the door through the linking member of the pulling bar. Since the automatic door closing arrangements are disposed above the ceiling and linked with the doors through the spaces within the carrier bars by the linking members, they are hidden from eyes of people using the revolving door system. Thus, the appearance of the system is kept neat and tidy.
According to a fifth feature of the invention, an error absorber is disposed between the door supporting structure and the upper or lower suspension device. The error absorber absorbs error which could occur in parallelism between the door supporting structure and the suspension devices during the door movement.
Due to variations in distance between the upper and lower suspension devices of the respective sets and variations in parallelism between the upper and lower rails, the engagement between the respective upper suspension devices and the upper rail and/or the engagement between the respective lower suspension devices and the lower rail may vary depending on the locations of the doors. For example, if the distance between the upper and lower rails increases at a certain point, the upper and lower suspension devices reaching that point leave away from each other, which results in undue force exerted to the door supporting structure. Without the error absorbers, such undue force may increase resistance against movement of the doors, resulting in local abrasion of the rails and the suspension devices or in damage in the door supporting structure and the suspension device. The error absorbers can absorb such error in parallelism.